Irradiation and Bevacizumab in High-Grade Glioma Retreatment Settings

Re-irradiation treatment regimens for patients with recurrent glioma - Evaluation of the optimal dose and best concurrent therapy

PURPOSE

Re-irradiation (reRT) is an effective treatment modality for patients with recurrent glioma. Data on dose escalation, the use of simulated integrated boost and concomitant therapy to reRT are still scarce. In this monocentric cohort of n = 223 patients we investigated the influence of reRT dose escalation as well as the concomitant use of bevacizumab (BEV) with regard to post-recurrence survival (PRS) and risk of radionecrosis (RN).

PATIENTS AND METHODS

Patients with recurrent glioma treated between July 2008 and August 2022 with reRT with BEV, reRT with temozolomide (TMZ) and reRT without concomitant systemic therapy were retrospectively analyzed. PRS and RN-free survival (RNFS) were calculated for all patients using the Kaplan-Meier estimator. Univariable and multivariable cox regression was performed for PRS and for RNFS. The reRT Risk Score (RRRS) was calculated for all patients.

RESULTS

Good, intermediate and poor risk of the RRRS translated into 11 months, 9 months and 7 months of median PRS (univariable: p = 0.008, multivariable: p = 0.013). ReRT was applied with a dose of ≤36 Gy (n = 140) or >36 Gy (n = 83). Concomitant bevacizumab (BEV) therapy was performed in n = 122 and concomitant temozolomide (TMZ) therapy in n = 32 patients. Median PRS was 10 months in patients treated with >36 Gy and 8 months in patients treated with ≤36 Gy (univariable: p = 0.032, multivariable: p = 0.576). Regarding concomitant TMZ therapy, median PRS was 14 months vs. 9 months for patients treated with or without TMZ (univariable: p = 0.041, multivariable: p = 0.019). No statistically significant influence on PRS was seen for concomitant BEV therapy in this series. RN was less frequent for reRT with concomitant BEV, (17/122; 13.9 %) than for reRT without BEV (30/101; 29.7 %). Regarding RNFS, the hazard ratio for reRT with BEV was 0.436 (univariable; p = 0.006) and 0.479 (multivariable; p = 0.023), respectively. ReRT dose did not show statistical significance in regards to RN (univariable: p = 0.073, multivariable: p = 0.404). RNFS was longer for patients receiving concomitant BEV to reRT than for patients treated with reRT only (mean 31.7 vs. 30.9 months, p = 0.004).

CONCLUSION

In this cohort, in patients treated with concomitant BEV therapy RN was less frequently detected and in patients treated with concomitant TMZ longer PRS was observed. Based on these results, the best concomitant therapy and the optimal dose should be decided on a patient-by-patient basis.

Preclinical and clinical advances to overcome hypoxia in glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most common adult primary brain tumor. The standard clinical treatment of GBM includes a maximal surgical resection followed by concomitant radiotherapy (RT) and chemotherapy sessions with Temozolomide (TMZ) in addition to adjuvant TMZ cycles. Despite the severity of this protocol, GBM is highly resistant and recurs in almost all cases while the protocol remains unchanged since 2005. Limited-diffusion or chronic hypoxia has been identified as one of the major key players driving this aggressive phenotype. The presence of hypoxia within the tumor bulk contributes to the activation of hypoxia signaling pathway mediated by the hypoxia-inducing factors (HIFs), which in turn activate biological mechanisms to ensure the adaptation and survival of GBM under limited oxygen and nutrient supply. Activated downstream pathways are involved in maintaining stem cell-like phenotype, inducing mesenchymal shift, invasion, and migration, altering the cellular and oxygen metabolism, and increasing angiogenesis, autophagy, and immunosuppression. Therefore, in this review will discuss the recent preclinical and clinical approaches that aim at targeting tumor hypoxia to enhance the response of GBM to conventional therapies along with their results and limitations upon clinical translation.

Updates in the Management of Recurrent Glioblastoma Multiforme

BACKGROUND

 Glioblastoma is the most aggressive and diffusely infiltrative primary brain tumor. Recurrence is almost universal even after all primary standard treatments. This article aims to review the literature and update the standard treatment strategies for patients with recurrent glioblastoma.

METHODS

 A systematic search was performed with the phrase "recurrent glioblastoma and management" as a search term in PubMed central, Medline, and Embase databases to identify all the articles published on the subject till December 2020. The review included peer-reviewed original articles, clinical trials, review articles, and keywords in title and abstract.

RESULTS

 Out of 513 articles searched, 73 were included in this review after screening for eligibility. On analyzing the data, most of the studies report a median overall survival (OS) of 5.9 to 11.4 months after re-surgery and 4.7 to 7.6 months without re-surgery. Re-irradiation with stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) result in a median OS of 10.2 months (range: 7.0-12 months) and 9.8 months (ranged: 7.5-11.0 months), respectively. Radiation necrosis was found in 16.6% (range: 0-24.4%) after SRS. Chemotherapeutic agents like nitrosourea (carmustine), bevacizumab, and temozolomide (TMZ) rechallenge result in a median OS in the range of 5.1 to 7.5, 6.5 to 9.2, and 5.1-13.0 months and six months progression free survival (PFS-6) in the range of 13 to 17.5%, 25 to 42.6%, and 23 to 58.3%, respectively. Use of epithelial growth factor receptor (EGFR) inhibitors results in a median OS in the range of 2.0 to 3.0 months and PFS-6 in 13%.

CONCLUSION

 Although recurrent glioblastoma remains a fatal disease with universal mortality, the literature suggests that a subset of patients may benefit from maximal treatment efforts.

Re-irradiation for high-grade gliomas: Has anything changed?

Optimal management after recurrence or progression of high-grade gliomas is still undefined and remains a challenge for neuro-oncology multidisciplinary teams. Improved radiation therapy techniques, new imaging methods, published experience, and a better radiobiological knowledge of brain tissue have positioned re-irradiation (re-RT) as an option for many of these patients. Decisions must be individualized, taking into account the pattern of relapse, previous treatment, and functional status, as well as the patient’s preferences and expected quality of life. Many questions remain unanswered with respect to re-RT: Who is the most appropriate candidate, which dose and fractionation are most effective, how to define the target volume, which imaging technique is best for planning, and what is the optimal timing? This review will focus on describing the most relevant studies that include re-RT as salvage therapy, with the aim of simplifying decision-making and designing the best available therapeutic strategy.

Accelerator-based BNCT for patients with recurrent glioblastoma: a multicenter phase II study

Background

Boron neutron capture therapy (BNCT) utilizes tumor-selective particle radiation. This study aimed to assess the safety and efficacy of accelerator-based BNCT (AB-BNCT) using a cyclotron-based neutron generator (BNCT 30) and ¹⁰B-boronophenylalanine (SPM-011) in patients with recurrent malignant glioma (MG) (primarily glioblastoma [GB]).

Methods

This multi-institutional, open-label, phase II clinical trial involved 27 recurrent MG cases, including 24 GB cases, who were enrolled from February 2016 to June 2018. The study was conducted using the abovementioned AB-BNCT system, with 500 mg/kg SPM-011 (study code: JG002). The patients were bevacizumab-naïve and had recurrent MG after standard treatment. The primary endpoint was the 1-year survival rate, and the secondary endpoints were overall survival (OS) and progression-free survival (PFS). Results were compared to those of a previous Japanese domestic bevacizumab trial for recurrent GB (JO22506).

Results

The 1-year survival rate and median OS of the recurrent GB cases in this trial were 79.2% (95% CI: 57.0–90.8) and 18.9 months (95% CI: 12.9–not estimable), respectively, whereas those of JO22506 were 34.5% (90% CI: 20.0–49.0) and 10.5 months (95% CI: 8.2–12.4), respectively. The median PFS was 0.9 months (95% CI: 0.8–1.0) by the RANO criteria. The most prominent adverse event was brain edema. Twenty-one of 27 cases were treated with bevacizumab following progressive disease.

Conclusions

AB-BNCT demonstrated acceptable safety and prolonged survival for recurrent MG. AB-BNCT may increase the risk of brain edema due to re-irradiation for recurrent MG; however, this appears to be controlled well with bevacizumab.

Local treatment for relapsing glioblastoma: A decision-making tree for choosing between reirradiation and second surgery

In case of circumscribed recurrent glioblastoma (rec-GBM), a second surgery (Re-S) and reirradiation (Re-RT) are local strategies to consider. The aim is to provide an algorithm to use in the daily clinical practice. The first step is to consider the life expectancy in order to establish whether the patient should be a candidate for active treatment. In case of a relatively good life expectancy (>3 months) and a confirmed circumscribed disease(i.e. without multiple lesions that are in different lobes/hemispheres), the next step is the assessment of the prognostic factors for local treatments. Based on the existing prognostic score systems, patients who should be excluded from local treatments may be identified; based on the validated prognostic factors, one or the other local treatment may be preferred. The last point is the estimation of expected toxicity, considering patient-related, tumor-related and treatment-related factors impacting on side effects. Lastly, patients with very good prognostic factors may be considered for receiving a combined treatment.

Improving the Efficacy of Tumor Radiosensitization Through Combined Molecular Targeting

Chemoradiation, either alone or in combination with surgery or induction chemotherapy, is the current standard of care for most locally advanced solid tumors. Though chemoradiation is usually performed at the maximum tolerated doses of both chemotherapy and radiation, current cure rates are not satisfactory for many tumor entities, since tumor heterogeneity and plasticity result in chemo- and radioresistance. Advances in the understanding of tumor biology, a rapidly growing number of molecular targeting agents and novel technologies enabling the in-depth characterization of individual tumors, have fuelled the hope of entering an era of precision oncology, where each tumor will be treated according to its individual characteristics and weaknesses. At present though, molecular targeting approaches in combination with radiotherapy or chemoradiation have not yet proven to be beneficial over standard chemoradiation treatment in the clinical setting. A promising approach to improve efficacy is the combined usage of two targeting agents in order to inhibit backup pathways or achieve a more complete pathway inhibition. Here we review preclinical attempts to utilize such dual targeting strategies for future tumor radiosensitization.

Clinical Outcomes in Patients with Recurrent Glioblastoma Treated with Proton Beam Therapy Reirradiation: Analysis of the Multi-Institutional Proton Collaborative Group Registry

Purpose

As a means of limiting normal tissue toxicity, proton-beam therapy (PBT) is an emerging radiation modality for glioblastoma (GBM) reirradiation. However, data for recurrent GBM treated with PBT reirradiation is limited. Therefore, we analyzed treatment patterns, toxicities, and clinical outcomes of patients with recurrent GBM treated with PBT reirradiation using the multi-institutional Proton Collaborative Group registry.

Methods and Materials

Prospectively collected data for patients with recurrent GBM who underwent PBT while enrolled in Proton Collaborative Group study 01-009 (NCT01255748) were analyzed. We evaluated overall survival (OS), progression-free survival (PFS), and toxicity. Toxicities were scored per the Common Terminology Criteria for Adverse Events, version 4.0. Descriptive statistics were used to report patient, tumor, and treatment characteristics. Multivariable analyses (MVA) for toxicity were conducted using logistic regression. The Kaplan-Meier method was used to calculate OS and PFS. MVA for OS and PFS was conducted using Cox proportional-hazards models. The SAS statistical software was used for the analysis.

Results

We identified 45 recurrent patients with GBM who underwent PBT reirradiation between 2012 and 2018. The median time between initial GBM diagnosis and recurrence was 20.2 months. The median follow-up time from PBT reirradiation was 10.7 months. Median PFS was 13.9 months (95% confidence interval [CI], 8.23-20.0 months) and median OS was 14.2 months (95% CI, 9.6-16.9 months) after PBT reirradiation. One patient experienced an acute grade 3 toxicity, 4 patients experienced late grade 3 toxicity (no grade ≥4 toxicities). MVA revealed that prior surgery was associated with a 91.3% decreased hazard of death (hazard ratio: 0.087; 95% CI, 0.02-0.42; P < .01). No explanatory variables were associated with PFS or grade 3 toxicities.

Conclusions

This is the largest series to date reporting outcomes for PBT reirradiation of patients with recurrent GBM. Our analysis indicates that PBT is well tolerated and offers efficacy rates comparable with previously reported photon reirradiation.

The role of large volume re-irradiation with Bevacizumab in chemorefractory high grade glioma

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Large volume reRT is a viable treatment for refractory recurrent high-grade glioma.

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Bevacizumab facilitates large volume reRT by reducing the risk of CNS radionecrosis.

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Patient selection for reRT needs more work but should be guided by performance status.

Background and purpose

Current practice in re-irradiation (reRT) of previously treated high-grade gliomas (HGG) has generally been limited to small volume reRT with stereotactic procedures. Less evidence exists for large volume reRT involving treatment volumes equivalent to that used at initial diagnosis. The primary aim of this study was to investigate the outcome of large volume reRT delivered in combination with Bevacizumab (BEV) in patients with recurrent chemorefractory HGG.

Methods and materials

Patients with HGG managed with reRT were entered prospectively into a database. Clinicopathological features were recorded including timing of reRT, use of BEV and Dosimetric data. Median survival following reRT was the primary endpoint and association with clinicopathological factors was assessed with cox regression models.

Results

Sixty seven patients in total were managed with reRT, 51 patients had glioblastoma and 16 had anaplastic glioma. The median PTV was 145.3 cm³. Median OS post reRT was 7.8 months (95% CI 6.3–9.2 months) in the total cohort and 7.5 months (95% CI: 6.6–8.3 months) for GBM patients. In multivariate analysis of the whole cohort, IDH1 mutation status (p = 0.041) and ECOG status prior to reRT (<0.001) were significantly associated with OS. In terms of safety and toxicity, the majority of patients (66.5%) were ECOG 0–2 three months after treatment. In total, four episodes of suspected radiation necrosis occurred, all in patients treated without upfront BEV.

Conclusion

Large volume reRT with bevacizumab is a feasible late salvage option in patients with recurrent HGG and offers meaningful prolongation of survival with low toxicity.

Bevacizumab reduces toxicity of reirradiation in recurrent high-grade glioma

PURPOSE

The role of bevacizumab (BEV) in the setting of reirradiation (reRT) of malignant glioma recurrences is poorly defined. At our institution, reRT plus BEV was routinely used until its disapproval for glioma treatment by the European Medical Agency. Accordingly, reRT was applied without the addition of BEV since 2017. Here we present for the first time outcome and toxicity profiles of reRT plus BEV and reRT alone for malignant glioma recurrences.

PATIENTS AND METHODS

All adult patients consecutively undergoing reRT of a recurrent malignant glioma (37 anaplastic astrocytoma, WHO III; 124 glioblastoma, WHO IV) between 2007 and 2017 were included. In one group of patients, BEV (10 mg/kg bodyweight) was applied concomitantly on days 1 and 15 of reRT. Radiation toxicity referred to clinically significant toxicities of proven symptomatic radionecrosis (RN) and symptomatic oedema (SE) requiring steroid treatment for more than six weeks after reRT. Post-recurrence survival (PRS) and freedom from RN/SE were estimated with the Kaplan-Meier method. Prognostic factors were obtained from proportional hazards models.

RESULTS

BEV plus reRT was applied in 124 and reRT alone in 37 patients. Both groups were comparable in terms of their patient-, tumour-, and RT/reRT-related variables. PRS was independent from the applied reRT protocols. RN/SE was less frequently seen after reRT plus BEV absolutely (27/124 (21.8%) vs. 14/37 (37.8%) patients; p = 0.025) and over time (1-year RN/SE rate: 23.9% vs. 54.1%; p = 0.013). The unadjusted and adjusted hazard ratio for RN/SE was doubled in case of reRT alone. Absence of BEV remained the only risk factor for RN/SE in multivariate models (p = 0.026).

CONCLUSION

Concomitant BEV effectively reduces treatment toxicity of reRT and should be reconsidered in future reRT protocols.

Role of delayed salvage bevacizumab at symptomatic progression of chemorefractory glioblastoma

BACKGROUND

Assess benefit of salvage bevacizumab (BEV) at time of symptomatic progression in patients with refractory glioblastoma (GBM).

METHODS

Patients managed with adjuvant long course chemo-radiation therapy for GBM were entered into a prospective database. At chemorefractory symptomatic progression, patients were offered BEV or best supportive care. Re-irradiation (ReRT) was used with BEV in selected patients. BEV continued indefinitely until deterioration limited hospital based infusion. The primary endpoint was median survival calculated from date of decision for BEV to proceed (BEVstart), or decision to decline BEV (BEVreject).

RESULTS

Fifty-five patients were managed of which 48 patients have relapsed disease. The median survival post relapse was 6 months (95%CI: 4.6-7.4). At relapse, 28 patients received BEV with only 14% delivered at first relapse. The median number of BEV cycles was 8 (range 1-25). ReRT was subsequently used in 16 (33%) relapsed patients. BEV treated patients were associated with improved median survival post relapse with 9 months vs 3 months (p < 0.01). The median survival from BEV related decision-making at symptomatic refractory progression to death was 4 months (95%CI: 2.0-6.0). BEVstart was associated with improved survival from this date with median survival of 6 months vs 1 month with BEVreject (p < 0.01). Median survival with ReRT from this date was 8 months vs 3 months without ReRT (p = 0.01). In the BEV patients at eventual progression, death occurred at a median of 30 days post BEV cessation.

CONCLUSION

In this clinic managing selected patients with chemorefractory progressive glioblastoma, delayed salvage bevacizumab, often in combination with re-irradiation, may provide an increase in survival duration compared with best supportive care.

Reirradiation of recurrent high-grade glioma and development of prognostic scores for progression and survival

Background

Optimal techniques and patient selection for salvage reirradiation of high-grade glioma (HGG) are unclear. In this study, we identify prognostic factors for freedom from progression (FFP) and overall survival (OS) after reirradiation, risk factors for high-grade toxicity, and validate clinical prognostic scores.

Methods

A total of 116 patients evaluated between 2000 and 2018 received reirradiation for HGG (99 WHO grade IV, 17 WHO grade III). Median time to first progression after initial therapy was 10.6 months. Salvage therapies before reirradiation included surgery (31%) and systemic therapy (41%). Sixty-five patients (56%) received single-fraction stereotactic radiosurgery (SRS) as reirradiation. The median biologically effective dose (BED) was 47.25 Gy, and the median planning target volume (PTV) was 4.8 cc for SRS and 95.0 cc for non-SRS treatments. Systemic therapy was given concurrently to 52% and adjuvantly to 74% of patients.

Results

Median FFP was 4.9 months, and median OS was 11.0 months. Significant multivariable prognostic factors for FFP were performance status, time to initial progression, and BED; for OS they were age, time to initial progression, and PTV volume at recurrence. High-grade toxicity was correlated to PTV size at recurrence. Three-level prognostic scores were generated for FFP and OS, with cross-validated receiver operating characteristic area under the curve (AUC) of 0.640 and 0.687, respectively.

Conclusions

Clinical variables at the time of reirradiation for HGG can be used to prognosticate FFP and OS.

Re-irradiation for recurrent glioma: outcome evaluation, toxicity and prognostic factors assessment. A multicenter study of the Radiation Oncology Italian Association (AIRO)

INTRODUCTION

The prognosis of glioma is dismal, and almost all patients relapsed. At recurrence time, several treatment options are considered, but to date there is no a standard of care. The Neurooncology Study Group of the Italian Association of Radiation Oncology (AIRO) collected clinical data regarding a large series of recurrent glioma patients who underwent re-irradiation (re-RT) in Italy.

METHODS

Data regarding 300 recurrent glioma patients treated from May 2002 to November 2017, were analyzed. All patients underwent re-RT. Surgical resection, followed by re-RT with concomitant and adjuvant chemotherapy was performed. Clinical outcome was evaluated by neurological examination and brain MRI performed, 1 month after radiation therapy and then every 3 months.

RESULTS

Re-irradiation was performed at a median interval time (IT) of 16 months from the first RT. Surgical resection before re-RT was performed in 19% of patients, concomitant temozolomide (TMZ) in 16.3%, and maintenance chemotherapy in 29%. Total doses ranged from 9 Gy to 52.5 Gy, with a median biological effective dose of 43 Gy. The median, 1, 2 year OS were 9.7 months, 41% and 17.7%. Low grade glioma histology (p  ≪ 0.01), IT > 12 months (p = 0.001), KPS > 70 (p = 0.004), younger age (p = 0.001), high total doses delivered (p = 0.04), and combined treatment performed (p = 0.0008) were recorded as conditioning survival.

CONCLUSION

our data underline re-RT as a safe and feasible treatment with limited rate of toxicity, and a combined ones as a better option for selected patients. The identification of a BED threshold able to obtain a greater benefit on OS, can help in designing future prospective studies.

Boron Neutron Capture Therapy Combined with Early Successive Bevacizumab Treatments for Recurrent Malignant Gliomas - A Pilot Study

Recurrent malignant gliomas (RMGs) are difficult to control, and no standard protocol has been established for their treatment. At our institute, we have often treated RMGs by tumor-selective particle radiation called boron neutron capture therapy (BNCT). However, despite the cell-selectivity of BNCT, brain radiation necrosis (BRN) may develop and cause severe neurological complications and sometimes death. This is partly due to the full-dose X-ray treatments usually given earlier in the treatment course. To overcome BRN following BNCT, recent studies have used bevacizumab (BV). We herein used extended BV treatment beginning just after BNCT to confer protection against or ameliorate BRN, and evaluated; the feasibility, efficacy, and BRN control of this combination treatment. Seven patients with RMGs (grade 3 and 4 cases) were treated with BNCT between June 2013 and May 2014, followed by successive BV treatments. They were followed-up to December 2017. Median overall survival (OS) and progression-free survival (PFS) after combination treatment were 15.1 and 5.4 months, respectively. In one case, uncontrollable brain edema occurred and ultimately led to death after BV was interrupted due to meningitis. In two other cases, symptomatic aggravation of BRN occurred after interruption of BV treatment. No BRN was observed during the observation period in the other cases. Common terminology criteria for adverse events grade 2 and 3 proteinuria occurred in two cases and necessitated the interruption of BV treatments. Boron neutron capture therapy followed by BV treatments well-prevented or well-controlled BRN with prolonged OS and acceptable incidence of adverse events in our patients with RMG.

Re-irradiation of recurrent glioblastoma as part of a sequential multimodality treatment concept

PURPOSE

The aim of this retrospective study was to evaluate survival outcomes in well-performing, mainly, young patients receiving a sequence of all available therapeutic options for relapsed glioblastoma, including re-irradiation.

METHODS

We performed a retrospective analysis of 27 patients irradiated twice for glioblastoma between 2008 and 2016. In the first line, all had surgical treatment of the tumor followed by radiotherapy with a total dose of 60 Gy and temozolomide. All re-irradiated patients were treated with a total dose of 36 Gy in 12 fractions. The endpoints were death from glioblastoma or any cause, and toxicity after re-irradiation.

RESULTS

The median follow-up of survivors was 35.6 months. At the time of analysis, 25 patients had died. The median time between first and second radiotherapy was 18.9 months (6.1-58.4). Re-irradiation was performed at different time points of first, second and third progression. The median overall survival after first diagnosis was 39.2 months. Five years after first surgery, nearly 20% of the patients were alive.

CONCLUSION

Carefully planned re-irradiation of the brain is a safe therapy for recurrent glioblastoma. Younger and well-performing patients benefit from all available therapy options. Every patient should be discussed in a multidisciplinary setting at each time point of tumor progression. Further prospective studies are needed to define the optimal time, dose and volume of re-irradiation.

Re-irradiation for malignant glioma: Toward patient selection and defining treatment parameters for salvage

Purpose

Reirradiation for recurrent glioma remains controversial without knowledge of optimal patient selection, dose, fractionation, and normal tissue tolerances. We retrospectively evaluated outcomes and toxicity after conventionally fractionated reirradiation for recurrent high-grade glioma, along with the impact of concurrent chemotherapy.

Methods and materials

We conducted a retrospective review of patients reirradiated for high-grade glioma recurrence between 2007 and 2016 (including patients with initial low-grade glioma). Outcome metrics included overall survival (OS), prognostic factors for survival, and treatment-related toxicity.

Results

Patients (n = 118; median age 47 years; median Karnofsky performance status score: 80) were re-treated at a median of 28 months (range, 5-214 months) after initial radiation therapy. The median reirradiation dose was 41.4 Gy (range, 12.6-54.0 Gy) to a median lesion volume of 202 cm³ (range, 20-901 cm³). The median cumulative (initial radiation and reirradiation combined) potential maximum brainstem dose was 76.9 Gy (range, 5.0-108.3 Gy) and optic apparatus dose was 56.0 Gy (range, 4.5-90.9 Gy). Of the patients, 56% received concurrent temozolomide, 14%, bevacizumab, and 11%, temozolomide plus bevacizumab; 19% had no chemotherapy. The planned reirradiation was completed by 90% of patients. Median OS from the completion of reirradiation was 9.6 months (95% confidence interval [CI], 7.5-11.7 months) for all patients and 14.0, 11.5, and 6.7 months for patients with initial grade 2, 3, and 4 glioma, respectively. On multivariate analysis, better OS was observed with a >24-month interval between radiation treatments (hazard ratio [HR]: 0.3; 95% CI, 0.2-0.5; P < .001), reirradiation dose >41.4 Gy (HR: 0.6; 95% CI, 0.4-0.9; P = .03), and gross total resection before reirradiation (HR: 0.6, 95% CI, 0.3-0.9; P = .02). Radiation necrosis and grade ≥3 late neurotoxicity were both minimal (<5%). No symptomatic persistent brainstem or optic nerve/chiasm injury was identified.

Conclusions

Salvage reirradiation, even at doses >41.4 Gy in conventional fractionation, along with chemotherapy, was safe and well tolerated with meaningful survival duration. These data provide information that may be useful in implementing safe reirradiation treatments for appropriately selected patients and guiding future studies to define optimal reirradiation doses, maximal safe doses to critical structures, and the role of systemic therapy.

Modern reirradiation for recurrent gliomas can safely delay tumor progression

BACKGROUND

Despite advances in modern therapy, high-grade gliomas continue to portend a dismal prognosis and nearly all patients will experience relapse. Unfortunately, salvage options remain limited. In this study, we assessed outcomes for patients with recurrent gliomas treated with reirradiation.

METHODS

We retrospectively identified 48 glioma patients treated with reirradiation between 2013 and 2016. All had radiographic or pathologic evidence of recurrence. Prognostic factors were abstracted from the electronic medical record.

RESULTS

Initial surgery included biopsy in 15, subtotal resection in 21, and gross total resection in 12. Initial chemotherapy included temozolomide (TMZ) in 31, TMZ+dasatinib in 7, TMZ+vorinostat in 3, and procarbazine, lomustine, and vincristine in 2. The median dose of primary radiotherapy was 60 Gy delivered in 30 fractions. Median overall survival (OS) and progression-free survival (PFS) from initial diagnosis were 3.2 and 1.7 years, respectively. A total of 36 patients failed salvage bevacizumab before reirradiation. Salvage surgery was performed before reirradiation in 21 patients. Median time to reirradiation was 1.7 years. Median follow-up was 13.7 months from reirradiation. Concurrent systemic therapy was given in 33 patients (bevacizumab in 27, TMZ in 8, and lomustine in 2). Median PFS and OS after reirradiation were 3.2 and 6.3 months, respectively. Radionecrosis occurred in 4 patients and no radionecrosis was seen in patients receiving concurrent bevacizumab with reirradiation (0% vs 19%, P = .03).

CONCLUSIONS

Reirradiation may result in delayed tumor progression with acceptable toxicity. Prospective trials are needed to determine the impact of reirradiation on tumor progression and quality of life.

Advances in Radiotherapy for Glioblastoma

External beam radiotherapy (RT) has long played a crucial role in the treatment of glioblastoma. Over the past several decades, significant advances in RT treatment and image-guidance technology have led to enormous improvements in the ability to optimize definitive and salvage treatments. This review highlights several of the latest developments and controversies related to RT, including the treatment of elderly patients, who continue to be a fragile and vulnerable population; potential salvage options for recurrent disease including reirradiation with chemotherapy; the latest imaging techniques allowing for more accurate and precise delineation of treatment volumes to maximize the therapeutic ratio of conformal RT; the ongoing preclinical and clinical data regarding the combination of immunotherapy with RT; and the increasing evidence of cancer stem-cell niches in the subventricular zone which may provide a potential target for local therapies. Finally, continued development on many fronts have allowed for modestly improved outcomes while at the same time limiting toxicity.

Challenges and opportunities of using stereotactic body radiotherapy with anti-angiogenesis agents in tumor therapy

Microvessels promote proliferation of tumor cells by delivering oxygen and nutrients, but rapid growth of tumors results in unmet demands for oxygen and nutrients, thereby creating a hypoxia microenvironment. Under hypoxic conditions, vascular endothelial cells (ECs) initiate the formation of immature and abnormal microvasculature. This results in leakage and tortuosity that facilitates tumor cell invasion, metastasis and resistance to cytotoxic treatment. Radiotherapy (RT) is a vital tumor treatment modality. Currently, more than 60% of patients with malignant tumors receive RT at certain points during their treatment. Hypoxia induced by abnormal microvessels can hamper the cytotoxic effect of ionizing radiation, particularly, stereotactic body radiotherapy (SBRT). Anti-angiogenesis (AA) agents are known to reduce and renormalize microvessels in tumors, and hence alleviate hypoxia. The combination of AA agents with SBRT may have a synergistic role in inhibiting the growth of tumors. On the contrary, large doses of irradiation may affect tumor microvessels itself. In this review, we aim to clarify the relationship between SBRT and microvessel formation in tumors. In addition, we provide a retrospective analysis of the combination therapy involving SBRT and AA agents in preclinical and clinical practice to define its role in anti-tumor treatment.

Reirradiation with concurrent bevacizumab for recurrent high-grade gliomas in adult patients

PURPOSE

To analyse feasibility, prognostic factors and patterns of recurrence after concurrent reirradiation and bevacizumab for recurrent high-grade gliomas.

PATIENTS AND METHODS

Between 2009 and 2015, 35 patients (median 57-year-old; 21 men, 14 women) with WHO grade III (n=11) or grade IV (n=24) gliomas were included in this retrospective and consecutive single-centre study. All patients received bevacizumab (median number of treatments: 12) concomitant with reirradiation (median dose: 45Gy, median number of fractions: 18) for recurrence with median 22 months (range: 5.6-123.7 months) from first irradiation (median dose: 60Gy).

RESULTS

The median follow-up was 9.2 months from reirradiation. The median overall survival from reirradiation was 10.5 months (95% confidence interval [95% CI]: 4.9-16.1) and the progression-free survival from reirradiation was 6.7 months (95% CI: 2.9-10.5). The median overall survival from initial diagnosis was 44.6 months (95% CI: 32-57.1). No grade 3 toxicity or above was reported. Prognostic factors significantly correlated with better overall survival in univariate analysis were: age at least 55 (P=0.024), initial surgery (P=0.003), and 2Gy equivalent dose (EQD2) at least 50Gy at reirradiation (P=0.046). Twenty-two patients bevacizumab-naïve at time of reirradiation had a significantly increased overall survival from reirradiation compared to patients treated with reirradiation after bevacizumab failure (17.7 vs. 5.4 months, P<0.001) as well as overall survival from initial diagnosis (58.9 vs. 33.5 months, P=0.006). This outcome was similar in patients with initial glioblastomas (P=0.018) or anaplastic gliomas (P=0.021). There was no correlation between overall survival and gross tumour volume or planning target volume, frontal localization, or number of salvage therapies before reirradiation (P>0.05).

CONCLUSIONS

Concomitant reirradiation with bevacizumab in high-grade recurrent gliomas shows encouraging results in terms of survival and toxicities. Our data suggest that reirradiation should be favoured at initiation of bevacizumab, with EQD2 at least 50Gy.

Expert consensus on re-irradiation for recurrent glioma

Purpose

To investigate radiation oncologists’ opinions on important considerations to offering re-irradiation (re-RT) as a treatment option for recurrent glioma.

Materials and methods

A survey was conducted with 13 radiation oncologists involved in the care of central nervous system tumor patients. The survey was comprised of 49 questions divided into 2 domains: a demographic section (10 questions) and a case section (5 re-RT cases with 5 to 6 questions representing one or several re-RT treatment dilemmas as may be encountered in the clinic). Respondents were asked to rate the relevance of various factors to offering re-RT, respond to the cases with a decision to offer re-RT vs. not, volume to be treated, margins to be employed, dose/fractionation suggested and any additional comments with respect to rationale in each scenario.

Results

Sixty nine percent of responders have been practicing for greater than 10 years and 61% have re-RT 20 to 100 patients to date, with 54% seeing 2–5 re-RT cases per month and retreating 1–2 patients per month. Recurrent tumor volume, time since previous radiation therapy, previously administered dose to organs at risk and patient performance status were rated by the majority of responders (85%, 92%, 77%, and 69% respectively) as extremely relevant or very relevant to offering re-RT as an option.

Conclusion

The experts’ practice of re-RT is still heterogeneous, reflecting the paucity of high-quality prospective data available for decision-making. Nevertheless, practicing radiation oncologists can support own decisions by referring to the cases found suitable for re-RT in this survey.

Electronic supplementary material

The online version of this article (10.1186/s13014-017-0928-3) contains supplementary material, which is available to authorized users.

Survival and complications of stereotactic radiosurgery: A systematic review of stereotactic radiosurgery for newly diagnosed and recurrent high-grade gliomas

BACKGROUND

Utilization of stereotactic radiosurgery (SRS) for treatment of high-grade gliomas (HGGs) has been slowly increasing with variable reported success rates.

OBJECTIVE

Systematic review of the available data to evaluate the efficacy of SRS as a treatment for HGG with regards to median overall survival (OS) and progression-free survival (PFS), in addition to ascertaining the rate of radiation necrosis and other SRS-related major neurological complications.

METHODS

Literature searches were performed for publications from 1992 to 2016. The pooled estimates of median PFS and median OS were calculated as a weighted estimate of population medians. Meta-analyses of published rates of radiation necrosis and other major neurological complications were also performed.

RESULTS

Twenty-nine studies reported the use of SRS for recurrent HGG, and 16 studies reported the use of SRS for newly diagnosed HGG. For recurrent HGG, the pooled estimates of median PFS and median OS were 5.42 months (3-16 months) and 20.19 months (9-65 months), respectively; the pooled radiation necrosis rate was 5.9% (0-44%); and the pooled estimates of major neurological complications rate was 3.3% (0-23%). For newly diagnosed HGG, the pooled estimates of median PFS and median OS were 7.89 months (5.5-11 months) and 16.87 months (9.5-33 months) respectively; the pooled radiation necrosis rate was 6.5% (0-33%); and the pooled estimates of other major neurological complications rate was 1.5% (0-25%).

CONCLUSION

Our results suggest that SRS holds promise as a relatively safe treatment option for HGG. In terms of efficacy at this time, there are inadequate data to support routine utilization of SRS as the standard of care for newly diagnosed or recurrent HGG. Further studies should be pursued to define more clearly the therapeutic role of SRS.

Multicenter, Phase 1, Dose Escalation Study of Hypofractionated Stereotactic Radiation Therapy With Bevacizumab for Recurrent Glioblastoma and Anaplastic Astrocytoma

PURPOSE

To establish the maximum tolerated dose of a 3-fraction hypofractionated stereotactic reirradiation schedule when delivered with concomitant bevacizumab to treat recurrent high-grade gliomas.

METHODS AND MATERIALS

Patients with recurrent high-grade glioma with Karnofsky performance status ≥60, history of standard fractionated initial radiation, tumor volume at recurrence ≤40 cm³, and absence of brainstem or corpus callosum involvement were eligible. A standard 3+3 phase 1 dose escalation trial design was utilized, with dose-limiting toxicities defined as any grade 3 to 5 toxicities possibly, probably, or definitely related to radiation. Bevacizumab was given at a dose of 10 mg/kg every 2 weeks. Hypofractionated stereotactic reirradiation was initiated after 2 bevacizumab doses, delivered in 3 fractions every other day, starting at 9 Gy per fraction.

RESULTS

A total of 3 patients were enrolled at the 9 Gy × 3 dose level cohort, 5 in the 10 Gy × 3 cohort, and 7 in the 11 Gy × 3 cohort. One dose-limiting toxicity of grade 3 fatigue and cognitive deterioration possibly related to hypofractionated stereotactic reirradiation was observed in the 11 Gy × 3 cohort, and this dose was declared the maximum tolerated dose in combination with bevacizumab. Although no symptomatic radionecrosis was observed, substantial treatment-related effects and necrosis were observed in resected specimens. The intent-to-treat median overall survival was 13 months.

CONCLUSIONS

Reirradiation using a 3-fraction schedule with bevacizumab support is feasible and reasonably well tolerated. Dose-escalation was possible up to 11 Gy × 3, which achieves a near doubling in the delivered biological equivalent dose to normal brain, in comparison with our previous 6 Gy × 5 schedule. Promising overall survival warrants further investigation.

Intensity modulated radiation therapy with pulsed reduced dose rate as a reirradiation strategy for recurrent central nervous system tumors: An institutional series and literature review

BACKGROUND

Pulsed reduced dose rate (PRDR) is a reirradiation technique that potentially overcomes volume and dose limitations in the setting of previous radiation therapy for recurrent central nervous system (CNS) tumors. Intensity modulated radiation therapy (IMRT) has not yet been reported as a PRDR delivery technique. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for CNS reirradiation.

METHODS AND MATERIALS

A total of 24 patients with recurrent brain tumors received PRDR reirradiation between August 2012 and December 2014. Twenty-two patients were planned with IMRT. Linear accelerators delivered an effective dose rate of 0.0667 Gy/minute. Data collected included number of prior interventions, diagnosis, tumor grade, radiation therapy dose and fractionation, normal tissue dose, radiation therapy planning parameters, time to progression, overall survival, and adverse events.

RESULTS

The median time to PRDR from completion of initial radiation therapy was 47.8 months (range, 11-389.1 months). The median PRDR dose was 54 Gy (range, 38-60 Gy). The mean planning target volume was 369.1 ± 177.9 cm³. The median progression-free survival and 6-month progression-free survival after PRDR treatment was 3.1 months and 31%, respectively. The median overall survival and 6-month overall survival after PRDR treatment was 8.7 months and 71%, respectively. Fifty percent of patients had ≥4 chemotherapy regimens before PRDR. Toxicity was similar to initial treatment, including no cases of radiation necrosis.

CONCLUSION

IMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent CNS tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated. Prospective studies are necessary to determine the optimal timing of PRDR reirradiation, the role of concurrent systemic agents, and the ideal patient population who would receive the maximal benefit from this treatment approach.

SUMMARY

Intensity modulated radiation therapy (IMRT) has not yet been reported as a pulsed reduced dose rate (PRDR) delivery technique for recurrent brain tumors and may allow for safe and comprehensive reirradiation for large volume tumors. We reviewed our IMRT PRDR outcomes and toxicity and reviewed the literature of available PRDR series for recurrent central nervous system tumors. We conclude that IMRT PRDR reirradiation is a feasible and appropriate treatment strategy for large volume recurrent brain tumors resulting in acceptable overall survival with reasonable toxicity in our patients who were heavily pretreated.

The evolving role for re-irradiation in the management of recurrent grade 4 glioma

Although significant gains have been realized in the management of grade 4 glioma, the majority of these patients will ultimately suffer local recurrence within the prior field of treatment. Clearly, novel local treatment strategies are required to improve patient outcomes. Concerns of toxicity have limited enthusiasm for the utilization of re-irradiation as a treatment option. However, using modern imaging technology and precision radiotherapy delivery techniques re-irradiation has proven a feasible option achieving both a palliative benefit and prolongation of survival with low toxicity rates. The evolution of re-irradiation as a treatment modality for recurrent grade 4 glioma is reviewed. In addition, potential targeted radiosensitizers to be used in conjunction with re-irradiation are also discussed.

Benefit of re-operation and salvage therapies for recurrent glioblastoma multiforme: results from a single institution

The optimal management of recurrent glioblastoma (GBM) has yet to be determined. We aim to assess the benefits of re-operation and salvage therapies (chemotherapy and/or re-irradiation) for recurrent GBM and to identify prognostic factors associated with better survival. All patients who underwent surgery for GBM between January 2005 and December 2012 followed by adjuvant radiotherapy, and who developed GBM recurrence on imaging were included in this retrospective study. Univariate and multivariate analysis was performed using Cox models in order to identify factors associated with overall survival (OS). One hundred and eighty patients treated to a dose of 60 Gy were diagnosed with recurrent GBM. At a median follow-up time of 6.2 months, the median survival (MS) from time of recurrence was 6.6 months. Sixty-nine patients underwent repeat surgery for recurrence based on imaging. To establish the benefits of repeat surgery and salvage therapies, 68 patients who underwent repeat surgery were matched to patients who did not based on extent of initial resection and presence of subventricular zone involvement at recurrence. MS for patients who underwent re-operation was 9.6 months, compared to 5.3 months for patients who did not have repeat surgery (p < 0.0001). Multivariate analysis in the matched pairs confirmed that repeat surgery with the addition of other salvage treatment can significantly affect patient outcome (HR 0.53). Re-operation with additional salvage therapies for recurrent GBM provides survival prolongation at the time of progression.

Bevacizumab and radiotherapy for the treatment of glioblastoma: brothers in arms or unholy alliance?

Glioblastoma (GBM) represents the most frequent primary brain tumor in adults and carries a dismal prognosis despite aggressive, multimodal treatment regimens involving maximal resection, radiochemotherapy, and maintenance chemotherapy. Histologically, GBMs are characterized by a high degree of VEGF-mediated vascular proliferation. In consequence, new targeted anti-angiogenic therapies, such as the monoclonal anti-VEGF-A antibody bevacizumab, have proven effective in attenuating tumor (neo)angiogenesis and were shown to possess therapeutic activity in several phase II trials. However, the role of bevacizumab in the context of multimodal therapy approaches appears to be rather complex. This review will give insights into current concepts, limitations, and controversies regarding the molecular mechanisms and the clinical benefits of bevacizumab treatment in combination with radio(chemo)therapy - particularly in face of the results of recent phase III trials, which failed to demonstrate convincing improvements in overall survival (OS).

Re-irradiation strategies in combination with bevacizumab for recurrent malignant glioma

The place of bevacizumab (BEV) in salvage re-irradiation (Re-RT) settings of malignant glioma is poorly defined. In the current study risk/benefit profiles of two BEV-based Re-RT protocols were analyzed and compared with that of salvage BEV plus irinotecan (BEV/IRI). According to interdisciplinary tumor board recommendations, patients were assigned to one of three BEV-based treatment protocols: (1) BEV/IRI, (2) Re-RT (36 Gy/18 fx) with concomitant BEV (Re-RT/BEV), and (3) Re-RT with concomitant/maintenance BEV (Re-RT/BEV→BEV). Prognostic factors were obtained from proportional hazards models. Adverse events were classified according to the NCI CTCAE, v4.0. 105 consecutive patients were enrolled from 08/2008 to 05/2014. Patients undergoing Re-RT experienced longer time intervals from initial diagnosis to BEV treatment (median: 22.0 months vs. 13.7 months, p = 0.001); those assigned to Re-RT/BEV→BEV rated better on the performance scale (median KPS_REC: 90 vs. 70, p = 0.013). Post-recurrence survival after BEV-based treatment (PRS) was longest after Re-RT/BEV→BEV (median: 13.1 months vs. 8 months, p = 0.006). PRS after Re-RT/BEV and BEV/IRI was similar. Multivariately, higher KPS_REC and Re-RT/BEV→BEV were associated with longer PRS. Treatment toxicity did not differ among groups. Re-RT/BEV→BEV is safe, feasible and effective and deserves further prospective evaluation.

Management of glioblastoma after recurrence: A changing paradigm

Glioblastoma remains the most common primary brain tumor after the age of 40years. Maximal safe surgery followed by adjuvant chemoradiotherapy has remained the standard treatment for glioblastoma (GBM). But recurrence is an inevitable event in the natural history of GBM with most patients experiencing it after 6-9months of primary treatment. Recurrent GBM poses great challenge to manage with no well-defined management protocols. The challenge starts from differentiating radiation necrosis from true local progression. A fine balance needs to be maintained on improving survival and assuring a better quality of life. Treatment options are limited and ranges from re-excision, re-irradiation, systemic chemotherapy or a combination of these. Re-excision and re-irradiation must be attempted in selected patients and has been shown to improve survival outcomes. To facilitate the management of GBM recurrences, a treatment algorithm is proposed.

Re-Irradiation for Recurrent Gliomas: Treatment Outcomes and Prognostic Factors

PURPOSE

The aim of this study was to evaluate the efficacy of re-irradiation in patients with recurrent gliomas and to identify subgroups for whom re-irradiation for recurrent gliomas is most beneficial.

MATERIALS AND METHODS

We retrospectively reviewed 36 patients with recurrent or progressive gliomas who received re-irradiation between January 1996 and December 2011. Re-irradiation was offered to recurrent glioma patients with good performance or at least 6 months had passed after initial radiotherapy (RT), with few exceptions.

RESULTS

Median doses of re-irradiation and initial RT were 45.0 Gy and 59.4 Gy, respectively. The median time interval between initial RT and re-irradiation was 30.5 months. Median overall survival (OS) and the 12-month OS rate were 11 months and 41.7%, respectively. In univariate analysis, Karnofsky performance status (KPS) ≥70 (p<0.001), re-irradiation dose ≥45 Gy (p=0.040), and longer time interval between initial RT and re-irradiation (p=0.040) were associated with improved OS. In multivariate analysis, KPS (p=0.030) and length of time interval between initial RT and re-irradiation (p=0.048) were important predictors of OS. A radiographically suspected mixture of radiation necrosis and progression after re-irradiation was seen in 5 patients.

CONCLUSION

Re-irradiation in conjunction with surgery could be a salvage treatment for selected recurrent glioma patients with good performance status and recurrence over a long time.

External beam re-irradiation, combination chemoradiotherapy, and particle therapy for the treatment of recurrent glioblastoma

Glioblastoma is a common aggressive primary malignant brain tumor, and is nearly universal in progression and mortality after initial treatment. Re-irradiation presents a promising treatment option for progressive disease, both palliating symptoms and potentially extending survival. Highly conformal radiation techniques such as stereotactic radiosurgery and hypofractionated radiosurgery are effective short courses of treatment that allow delivery of high doses of therapeutic radiation with steep dose gradients to protect normal tissue. Patients with higher performance status, younger age, and longer interval between primary treatment and progression represent the best candidates for re-irradiation. Multiple studies are also underway involving combinations of radiation and systemic therapy to bend the survival curve and improve the therapeutic index. In the multimodal treatment of recurrent high-grade glioma, the use of surgery, radiation, and systemic therapy should be highly individualized. Here we comprehensively review radiation therapy and techniques, along with discussion of combination treatment and novel strategies.

Stereotactic Radiosurgery for Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults and one of the most aggressive of all human cancers. GBM tumors are highly infiltrative and relatively resistant to conventional therapies. Aggressive management of GBM using a combination of surgical resection, followed by fractionated radiotherapy and chemotherapy has been shown to improve overall survival; however, GBM tumors recur in the majority of patients and the disease is most often fatal. There is a need to develop new treatment regimens and technological innovations to improve the overall survival of GBM patients. The role of stereotactic radiosurgery (SRS) for the treatment of GBM has been explored and is controversial. SRS utilizes highly precise radiation techniques to allow dose escalation and delivery of ablative radiation doses to the tumor while minimizing dose to the adjacent normal structures. In some studies, SRS with concurrent chemotherapy has shown improved local control with acceptable toxicities in select GBM patients. However, because GBM is a highly infiltrative disease, skeptics argue that local therapies, such as SRS, do not improve overall survival. The purpose of this article is to review the literature regarding SRS in both newly diagnosed and recurrent GBM, to describe SRS techniques, potential eligible SRS candidates, and treatment-related toxicities. In addition, this article will propose promising areas for future research for SRS in the treatment of GBM.

Efficacy and safety of bevacizumab for the treatment of glioblastoma

Glioblastoma (GBM) is the most common and devastating primary malignant intracranial tumor in adults. The current first-line treatment for patients with newly diagnosed GBM is surgical resection followed by radiotherapy plus concomitant and adjuvant temozolomide. This treatment protocol may prolong the survival period of the patient, however it is not curative and more effective therapeutic strategies are required. GBM is a type of highly vascularized tumor with increased expression levels of vascular endothelial growth factor (VEGF), which is a significant mediator of angiogenesis. Since angiogenesis is essential for tumor growth, anti-angiogenic therapies hold potential for the treatment of GBM, and targeting VEGF has demonstrated promising results in previous studies. Bevacizumab (BEV) is a recombinant humanized monoclonal antibody that inhibits VEGF and is approved by the US Food and Drug Administration as a monotherapy treatment for patients with recurrent GBM and is associated with manageable toxicity. Previous studies have demonstrated that BEV may be an effective treatment for recurrent GBM, with prolonged progression-free survival and overall survival, and maintained patient quality of life and functional status. The present review article briefly outlines the mechanism of action of BEV and summarizes the current literature and clinical trial research on the role of BEV for the treatment of patients with recurrent and newly diagnosed GBM.

Stereotactic radiosurgery (SRS) in high-grade glioma: judicious selection of small target volumes improves results

We present a retrospective review of 55 Stereotactic Radiosurgery (SRS) procedures performed in 47 consecutive patients with high-grade glioma (HGG). Thirty-three (70.2%) patients were diagnosed with glioblastoma and 14 (29.8%) with grade III glioma. The indications for SRS were small (up to 30 mm in diameter) locally progressing lesions in 32/47 (68%) or new distant lesions in 15/47 (32%) patients. The median target volume was 2.2 cc (0.2-9.5 cc) and the median prescription dose was 18 Gy (14-24 Gy). Three patients (5.5% incidence in 55 treatments) developed radiation necrosis. In eight cases (17%) patients received a second salvage SRS treatment to nine new lesions detected during follow-up. In 22/55 SRS treatments (40.0%) patients received concurrent chemo- or biological therapy, including temozolamide (TMZ) (15 patients), bevacizumab (BVZ) (6 patients) and carboplatin in one patient. Median time to progression after SRS was 5.0 months (1.0-96.4). Median survival time after SRS was 15.9 months (2.3-109.3) overall median survival (since diagnosis) was 37.4 months (9.6-193.6 months). Long-lasting responses (>12 months) after SRS were observed in 25/46 (54.3%) patients. We compared a matched (histology, age, KPS) cohort of patients with recurrent HGG treated with BVZ alone with the current study group. Median survival was significantly longer for SRS treated patients compared to the BVZ only cohort (12.6 vs. 7.3 months, p = 0.0102). SRS may be considered an effective salvage procedure for selected patients with small volume, recurrent high-grade gliomas. Long-term radiological control was observed in more than 50% of the patients.

Recurrent malignant gliomas

In almost all patients, malignant glioma recurs following initial treatment with maximal safe resection, conformal radiotherapy, and temozolomide. This review describes the many options for treatment of recurrent malignant gliomas, including reoperation, alternating electric field therapy, chemotherapy, stereotactic radiotherapy or radiosurgery, or some combination of these modalities, presenting the evidence for each approach. No standard of care has been established, though the antiangiogenic agent, bevacizumab; stereotactic radiotherapy or radiosurgery; and, perhaps, combined treatment with these 2 modalities appear to offer modest benefits over other approaches. Clearly, randomized trials of these options would be advantageous, and novel, more efficacious approaches are urgently needed.

Management of patients with recurrent glioblastoma using hypofractionated stereotactic radiotherapy

BACKGROUND

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The chance of cure is very limited due to treatment-refractory disease course with frequent recurrences despite aggressive multimodality management. In this retrospective study, we evaluated treatment outcomes of hypofractionated stereotactic radiotherapy (HFSRT) in the management of recurrent GBM and report our single-center experience.

METHODS

Twenty-eight patients receiving HFSRT for recurrent GBM between September 2008 and February 2014 were retrospectively assessed. Total radiotherapy dose was 25 Gy delivered in 5 fractions over 5 consecutive days for all patients. High-precision, image-guided volumetric modulated arc therapy was delivered with a linear accelerator using 6-MV photons using the frameless technique. Analyzed prognostic factors were age, gender, Karnofsky performance status (KPS), tumor location, planning target volume (PTV) size, overall survival (OS), progression-free survival (PFS), time interval between completion of treatment with Stupp protocol at primary diagnosis and recurrence.

RESULTS

Median follow-up time was 42 months (range 2-68). Median time interval between primary chemoradiotherapy and HFSRT was 11.2 months (range 4-57.9). Median OS and PFS calculated from reirradiation was 10.3 months and 5.8 months, respectively. Longer interval between initial treatment and recurrence (p = 0.01), smaller PTV size (p = 0.001), KPS ≥70 (p = 0.005) and younger age (p = 0.004) were associated with longer OS on statistical analysis.

CONCLUSION

HFSRT offers a feasible and effective salvage treatment option for recurrent GBM management. Prognostic factors associated with longer OS in our study were longer interval between initial treatment and recurrence, smaller PTV size, KPS ≥70 and younger age.

Fractionated stereotactic radiotherapy plus bevacizumab after response to bevacizumab plus irinotecan as a rescue treatment for high-grade gliomas

AIM

To evaluate the possibility of implementing a new scheme of rescue treatment after relapse or progression of high-grade glioma (HGG) treated at the first-line with bevacizumab and irinotecan (BVZ+CPT11), evaluating the response and toxicity of associating BVZ and fractionated stereotactic radiotherapy (BVZ+FSRT).

MATERIALS AND METHODS

We retrospectively analysed data from 59 patients with relapse of HGG. Nine patients with HGG relapse after treatment using the Stupp protocol that were treated with BVZ+CPT11 for progression between July 2007 and August 2012, after which the response was assessed according to the Revised Assessment in Neuro-Oncology (RANO) criteria. BVZ was administered at a dose of 10 mg/kg and FSRT up to a prescribed dose of 30 Gy, 500 cGy per fraction, three days a week. The median follow-up was 38 months.

RESULTS

The treatment was well-tolerated by all patients. The response after nuclear magnetic resonance imaging (MRI) at 3-6 months was progression in two patients, stable disease in four, and three patients had a partial response. The median overall survival (OS) from diagnosis until death or the last control was 36.8 months. The median progression-free survival (PFS) was 10.8 months. The results from tumour sub-group analysis indicated that the PFS was not statistically significant although it seemed that it was higher in grade-III. The OS was higher in grade-III gliomas.

CONCLUSIONS

The combination of BVZ+FSRT as a second-line HGG relapse rescue treatment is well-tolerated and seems to offer promising results. We believe that multi-centre prospective studies are needed to determine the long-term efficacy and toxicity of this therapeutic approach.

Recurrence pattern analysis after re-irradiation with bevacizumab in recurrent malignant glioma patients

Background

The aim of the present analysis was to evaluate the recurrence pattern in patients with recurrent malignant glioma after re-irradiation in combination with bevacizumab as there is limited data on how to optimally choose dose, fractionation and delineation margins.

Methods

Thirty-one patients with recurrent malignant glioma treated with re-irradiation and bevacizumab after previous chemoradiotherapy (concurrent temozolomide 75 mg/m²/d according to the EORTC/NCIC trial) and [¹⁸ F]FET-PET and/or MRI confirmed recurrence were retrospectively analyzed. Bevacizumab was applied twice during fractionated re-irradiation (10 mg/kg, d1 + d15, median 36 Gy, conventionally fractionated). Recurrence patterns were assessed by means of [¹⁸ F]FET-PET and/or MRI.

Results

Median follow-up was 34.0 months for all patients [95%-CI, 27.7-40.3] and median post-recurrence survival 10.8 months [95%-CI, 9.2-12.4]. Concerning the recurrence patterns, 61.3% of these were located in-field (19 patients), 22.6% were marginal (7 patients) and 16.1% ex-field (5 patients). No influence on the recurrence pattern was observed according to sex, WHO grade, maintenance chemotherapy or MGMT methylation status whereas planning target volume (PTV) size had a significant influence on the recurrence pattern (p = 0.032). PTV sizes > 75 ml were associated with a higher in-field recurrence rate and lower median post-recurrence progression-free survival (8.5 vs. 4.9 months, p = 0.016).

Conclusions

After the administration of re-irradiation with bevacizumab the recurrence pattern seems to be mainly centrally located. The PTV size was the main predictor for a marginal/ex-field recurrence.

Pathophysiology, diagnosis, and treatment of radiation necrosis in the brain

New radiation modalities have made it possible to prolong the survival of individuals with malignant brain tumors, but symptomatic radiation necrosis becomes a serious problem that can negatively affect a patient’s quality of life through severe and lifelong effects. Here we review the relevant literature and introduce our original concept of the pathophysiology of brain radiation necrosis following the treatment of brain, head, and neck tumors. Regarding the pathophysiology of radiation necrosis, we introduce two major hypotheses: glial cell damage or vascular damage. For the differential diagnosis of radiation necrosis and tumor recurrence, we focus on the role of positron emission tomography. Finally, in accord with our hypothesis regarding the pathophysiology, we describe the promising effects of the anti-vascular endothelial growth factor antibody bevacizumab on symptomatic radiation necrosis in the brain.

Large volume re-irradiation with bevacizumab is a feasible salvage option for patients with refractory high-grade glioma

BACKGROUND

Clinical studies of re-irradiation (ReRT) for relapsed high-grade glioma (HGG) have generally reported the use of small volume ReRT techniques such as stereotactic radiosurgery in selected patients with isolated focal relapse. This study reports the outcome with large-volume ReRT to manage the more common mescenario of extensive diffuse relapse of HGG.

METHODS

All HGG patients managed with an overlapping second course of radiation therapy (RT) for refractory progression of HGG between October 2009 and April 2013 were included. ReRT was initially used with bevacizumab (BEV), then used when disease was refractory to BEV, and finally used upfront with BEV-naïve patients. Tumor volume (GTV) and specific RT dosimetry factors, including the target volume treated (PTV), and cumulative RT dose maximum (Dmax), were analyzed. Median survival post ReRT was calculated using the Kaplan-Meier method and SPPS v19 software.

RESULTS

Eighteen HGG participants with refractory, bulky contrast-enhancing disease received ReRT. Thirteen participants had a maximum tumor diameter >5 cm, and median GTV was 54 cm³. Seven participants had BEV-refractory disease, and 8 participants were BEV naïve. ReRT dose was 35-40 Gy in 15 fractions; median PTV was 133 cm³, and median Dmax was 98.2 Gy. Median survival post ReRT for all participants was 8 months (95%CI, 5.8-10.2 months); with 10 months and 3 months for the BEV-naïve and BEV-refractory participants, respectively (P = .024). Two early participants, who were managed without BEV, were later salvaged with BEV, including one who required craniotomy for radiation necrosis at 6 weeks post RT. No other significant morbidity was reported.

CONCLUSION

ReRT combined with BEV is a feasible salvage treatment option for diffuse refractory HGG.

Hippocampal EUD in primarily irradiated glioblastoma patients

BACKGROUND

Radiation delivery for malignant brain tumors is gradually becoming more precise. Particularly the possibilities of sparing adjacent normal structures such as the hippocampus are increasing. To determine its radiation exposure more exactly, the equivalent uniform dose (EUD) of the hippocampus was compared with further treatment parameters. This way sparing options could be found.

METHODS

From the database of the University hospital of Munich 61 glioblastoma patients were selected who received primary radiotherapy in 2011. General data about the etiology, treatment course, survival of the patients and dose parameters were retrieved.

RESULTS

In a linear regression analysis the side of the tumor (left hippocampus: p < 0.001/right hippocampus: p = 0.009) and its temporal location (left hippocampus: p = 0.015/right hippocampus: p = 0.033) were identified as factors with a significant influence on the EUD of the respective hippocampus. Besides this, the size of the planning target volume (PTV) and the EUD of the hippocampus correlated significantly (p = 0.027; Pearson correlation = 0.291). The median PTV size of the tumor in the right hemisphere was 386.1 ml (range 131.2-910.7 ml), and in the left hemisphere 291.3 ml (range 146.0-588.9 ml) (Kruskal-Wallis test: p = 0.048). A dose quartile analysis showed that 31 patients had a high dose exposure of the hippocampus on one side while having a moderate dose exposure in the other side.

CONCLUSIONS

The radiation exposure of the respective hippocampus is dependent on the side where the tumor is located as well as on whether it is temporally located. The exposure of the contralateral hippocampus is further dependent on multiple additional factors - nevertheless a reasonable protection seems to be possible in about half of all cases.

Hypofractionated stereotactic radiosurgery with concurrent bevacizumab for recurrent malignant gliomas: the University of Alabama at Birmingham experience

BACKGROUND

Nearly all patients with malignant glioma will have disease recurrence. Our purpose was to define the treatment toxicity and efficacy of concurrent bevazicumab (BVZ) with hypofractionated stereotactic radiosurgery (SRS) of relatively larger targets for patients with recurrent MG.

METHODS

A retrospective review of 21 patients with recurrent malignant glioma (18 glioblastoma, 3 WHO grade III glioma), treated at initial diagnosis with surgery and standard chemoradiation, was performed. All patients had concurrent BVZ with hypofractionatedSRS, 30 Gy in 5 fractions, with or without concurrent chemotherapy (temozolomide or CCNU).

RESULTS

Median patient age was 54 years, median Karnofsky Performance Status was 80, and median target size was 4.3 cm (range, 3.4-7.5 cm). Eleven patients (52%) had previously failed BVZ. One patient had grade 3 toxicities (seizures, dysphasia), which resolved with inpatient admission and intravenous steroids/antiepileptics. Treatment-related toxicities were grade 3 (n = 1), grade 2 (n = 9), and grade 0-1 (n = 11). Kaplan-Meier median progression-free survival and overall survival estimates (calculated from start of SRS) for GBM patients (n = 18) were 11.0 and 12.5 months, respectively. Concurrent chemotherapy did not appear to show any statistically significant efficacy benefit or have any propensity for toxicity.

CONCLUSION

BVZ concurrent with hypofractionated SRS was well tolerated by this cohort of patients with relatively larger targets. Ongoing randomized trials with more moderate radiotherapy dosing may help establish the efficacy of this regimen, though intricacies of this approach, including patient selection, radiation target volume delineation/size, and optimal radiation dose, will need further evaluation.